Update sigstore/cosign-installer action to v4

Author: renovate[bot]

.github/workflows/docker.yml

@@ -30,7 +30,7 @@ jobs:
       # https://github.com/sigstore/cosign-installer
       - name: Install cosign
         if: github.event_name != 'pull_request'
-        uses: sigstore/cosign-installer@v3.10.0
+        uses: sigstore/cosign-installer@v4.0.0
         with:
           cosign-release: "v2.2.4"